VIDEO: Newton's 3rd Law by Veritasium

There is a gravitational force of attraction between the Earth and the moon, but is it mutual? That is, are the forces on the Earth and the moon equal? Most people would say no, the Earth exerts a greater force of attraction because it is larger and has more mass. This is a situation in which Newton's Third Law is relevant. Newton's Third Law says that for every force, there is an equal and opposite reaction force. So the force the Earth exerts on the moon must be exactly equal and opposite the force the moon exerts on the Earth. But how can that be - that the same size force keeps the moon orbiting, but barely affects the Earth? The answer is inertia - the tendency for all objects with mass to maintain their state of motion. Since the Earth has much more mass than the moon, it has greater inertia and therefore experiences much less acceleration for the same amount of force.

link to video on YouTube

VIDEO: Why Does the Moon Orbit Earth? by Veritasium

See! Sometimes people get it right! :-)

VIDEO: Scale Model of the Earth and Moon by Veritasium

If the Earth were a basket ball and the Moon a tennis ball, about how far apart would the balls need to be to accurately represent the distance between the Earth and Moon with a scale model?

Morning Message 10/9/08

Good Morning and Happy Friday!
Today is October 9, 2009.
Day 24 of School, 156 days left
Tiger Day: S

REMINDERS:

• We have pictures to take this morning. Our time slot is 9:15am.
• Math won’t start until 10am today and this coming Tuesday.
• Book Buddies has been rescheduled to today.
• No school on Monday: It’s Columbus Day!

In the News:
NASA crashed a rocket the size of a bus into the Moon this morning. On purpose! Now why would they do that? They were trying to figure out weather there is water on the moon. We’ll be studying the Moon later in the year... So let’s watch an animation of how it was supposed to work this morning.

Today, we need to talk and read about the last two regions: The Valley and Ridge and The Appalachian Plateau. On Tuesday, we’ll be shaping our VA pizzas.

To-Do List:

1. Complete your morning routine! Don’t forget about snack!
2. Add color to your geographic term illustrations. REMEMBER: (A) Each term must be clearly printed and (B) You must show or write where this type of land-/water- form is found in VA.